The way it was designed with the vents and fan prevent the moisture from saturating the wood. The small pan in the bottom filled with gravel and water is keeping the humidity inside still at 60 to 70 percent depending on the location of the sensor. I may have trouble with mold but the air flow should correct that on its own. That is the plan anyway, i will make changes as needed. So far there is no sign of the wood soaking up moisture, however time will tell. Any ideas im over looking?

It is also made from balsa wood. Balsa trees grow naturally in the humid rain forests of Central and South America. Its natural range extends south from Guatemala, through Central America, to the north and west coast of South America as far as Bolivia. So i was thinking this may hold up to the conditions better than other wood.